Professor David MacDonald, a zoologist at Oxford University, said: 'There is quite a lot of inconsistency in people's reactions to invasive species. The edible dormouse is quite widely thought of as being quite cuddly and so it doesn't seem to be worrying people, but we just don't know how much of a problem it will turn into.

'It has been increasing in numbers quite a lot recently although is still fairly confined in its range. We have seen with other invasive species, they can become a blight.'

His report, State of Britain's Mammals, lists American mink and grew squirrels as the most damaging non-native species to have become established in the UK.

Mink is thought to have escaped from fur farms around 1929 and has decimated the native water vole population.

Grey squirrels, introduced within the past two centuries, have led to a dramatic fall in the red squirrels known from the stories of Beatrix Potter.

Also on the list are red-necked wallabies, which have escaped into the wild from zoos and private collections and now exist in the Peak District, Bedfordshire and an island in Loch Lomand.

The report warns that other species have the potential to become future threats: including prairie dogs, short-clawed otters, raccoons, skunks and chipmunks.

Trevor Reynolds, invasive species advisor for the Environment Agency, said: 'Invasive species are a kind of biological pollution.

'It is likely that with climate change, the UK will see far more invasive species emerging. Stress caused to habitats by climate change will allow invasive species to take hold while increased storms could help spread invasive species around.'

Terima Kasih kerana membaca, Edible dormouse that Romans enjoyed as delicacy is named as Britain's No 1 pest